textproduct: Quad Cities

KEY MESSAGES

- Dangerous heat continues through Saturday, with peak heat indices of 100 to 110 degrees. Extreme heat warnings and heat advisories are in effect and have been extended.

- There remains a low risk (<15%) for isolated showers/storms this afternoon and Saturday afternoon/evening. There is a Marginal (level 1 of 5) risk for an isolated severe storm north of Hwy 20.

- Less humid Sunday/Monday, before heat and humidity returns mid-week. The overall pattern has a 55-70% probability of above normal temperatures through mid-September.

SHORT TERM /THROUGH SATURDAY/

Issued at 214 PM CDT Fri Sep 4 2026

Another hot and humid day is unfolding with 2pm temperatures in the upper 80s/low 90s and dewpoints in the low to mid 70s, similar to values 24-hrs ago. As a result, heat indices are above or nearing 100 degrees area-wide. Just to our northeast in southern WI, temperatures are in the 70s/low 80s thanks in part to the showers/storms this morning. In our area, a few isolated showers/storms occurred north Hwy 20 and along an outflow boundary in northwest IL that has since stalled just west of Sterling/Rock Falls.

Mostly dry and warm conditions are expected for most if not all the area the rest of the afternoon and evening. Widely scattered showers and isolated storms have developed in central and northeast IA in a weak 850-750mb convergent axis. CAM solutions are struggling with this activity as is often the case in weakly forced environments. The RAP would suggest some of this to reach our northwest counties, before we begin to lose instability after sunset and have added some slight chance PoPs for this. A brief heavy downpour and lightning will be the primary risks. If we had a stronger trigger, our 18z sounding showed a favorable environment for a couple strong to severe storms. All this said, weak deep layer flow, warm temps aloft, and meager mid level lapse rates will preclude a severe threat.

Overnight, some patchy fog will be possible along and north of Hwy 20 as winds go calm and clouds clear. Mild lows in the low 70s are forecast.

Saturday, hot and humid conditions will once again be seen for much of the area. A backdoor cold front will push through the CWA from northeast to southwest, finally bringing some relief to the heat. Models differ on when this front will be through the area and ahead of it, the heat will remain. For this reason and that this will be Day 6 of this oppressive heat and its cumulative effects, have extended the Extreme Heat Warning and Heat Advisory until 7pm Saturday south of a Independence, IA to Sterling, IL line. Remember to practice heat safety and drink plenty of water if outside for any holiday events. Regarding storm chances, all model solutions are largely dry but with a weak cool front moving through and any residual outflow boundaries left over this afternoon can't rule out some isolated showers/storms much like today occurring. No severe weather is anticipated.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/

Issued at 214 PM CDT Fri Sep 4 2026

Saturday night through Thursday Assessment...very high (>80%) confidence on above normal temperatures.

The upper level ridge retrogrades briefly into the Plains for the second half of the holiday weekend but will then push back east for the middle of next week. Thus after a brief reprieve from the heat Sunday/Monday, heat and humidity will surge back into the area Tuesday/Wednesday with heat indices approaching 100.

By late next week the overall flow pattern aloft de-amplifies slightly. This will allow temperatures to be closer to but still above normal.

Any rain chances the first half of next week are low (10-25%) and are confined to areas along/north of I-80. Thus there will be many hours of dry weather.

The models are attempting to bring a front into the area Tuesday night into Wednesday with the front progged to stall and wash out across the area. The proximity of the front has the model consensus giving slightly higher rain chances (30-50%) for late Tuesday night.

Once the front stalls and washes out across the area, its remnants would then provide the focus for rain chances the remainder of the week. However, even with a near daily chance of rain, the rain chances remain low (20-30%) with the better forcing remaining across the northern Plains and upper Midwest.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1226 PM CDT Fri Sep 4 2026

VFR conditions to persist through the TAF cycle at all terminals except DBQ. An outflow boundary to track southwest through northwest IL over the next 1-2 hours, but is expected to wash out before reaching MLI. A few isolated VFR showers will be possible this afternoon north of Hwy 30 dissipating prior to sunset. Clearing skies and calm wind in a moist environment to promote MVFR/IFR fog development primarily at DBQ overnight. A northerly wind shift will be seen Saturday, with a very low risk of shower activity just beyond this period.

CLIMATE

Issued at 558 AM CDT Thu Sep 3 2026

The Quad Cities (MLI) has had two days to start this month with 95 degree highs. If a third happens today, it would be the longest such stretch in September since September 4-6, 1990.

Record Warm Low Temperatures:

September 3: KDBQ: 73/1939 KMLI: 76/1939

September 4: KDBQ: 71/1912 KMLI: 74/2018

September 5: KDBQ: 76/1881 KMLI: 76/1925

DVN WATCHES/WARNINGS/ADVISORIES

IA...Heat Advisory until 7 PM CDT Saturday for IAZ040-051>053-066. Heat Advisory until 7 PM CDT this evening for IAZ041-042-054. Extreme Heat Warning until 7 PM CDT Saturday for IAZ063>065- 067-068-076>078-087>089-098-099. IL...Heat Advisory until 7 PM CDT Saturday for ILZ009. Heat Advisory until 7 PM CDT this evening for ILZ001-002-007. Extreme Heat Warning until 7 PM CDT Saturday for ILZ015>018- 024>026-034-035. MO...Extreme Heat Warning until 7 PM CDT Saturday for MOZ009-010.